Catalytic olefin metathesis has transformed chemical synthesis and offers exceptionally efficient pathways for synthesis of alkenes. A great number of commercially important molecules contain olefins. Such specialty chemicals include biologically active molecules, oleochemicals, renewables, fine chemicals, and polymeric materials, to name a few. Moreover, many reactions in organic chemistry require alkenes as starting materials. Accordingly, there remains an unmet need for improved methods and catalysts for metathesis reaction.